Reduction-gear change-speed unit



F. T. ProTTr-:lla'Y REDUCTION GEAR CHANGE SPEED UNIT Fil-ed July 19. 1929 A Aug. 4, 1931.

Patented Aug. 4, 1931 UNiTED STATES PATENT OFFICE FREDERICK T. POTTER, vF NEWTON, MASSACHUSETTS, .ASSIGNOR- TO STARK TOOL COM- PANY, OF WALTHAM, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS REDUCTION-GEAR CHANGE-SPEED UNIT Application led July 19,

This invention relates -to reduction gearing, andV particularly to change-speed reduction gearing of the type adapted for use with individual motor drive units for transmitting power from a motor to a machine for driving the latter. An object of this invention is to improve the construction of apparatus ofthe class described.

.. A gear set for an-individual motor drive unit should include reduction gearing for transmitting power delivered by the motor zoA at a reduced speed for driving a machine, and provision should also be made for delivering power to the driven machine at different operatingl speeds to facilitate the carrying out of different operations. The driving motors and the gear sets are usually made by different manufacturers, and it is advantageous to havea gear set which may be readily connected with a standard motor and which is not only compact and accessible in itself, but

' which is adapted for connection between the motor and the machine in such a manner as to permit the entire motor drive unit tofoccupy minimum space and, preferably, to occupy space which is not otherwise useful and which also affords aconvenient and accessi- 'ble location for the unit.

Some of the more specific objects of this invention are to provide change-speed reduction gearing of rugged Aand compact conf gear set, or removing orotherwise disturbing other elements either of the motor ldrive unit or of thedriven machine; to provide ,relatively simple means consisting' of few parts for assuring positive operation of the ychange-speed gearing and for preventing damage ,to the apparatusy during the operation of the lchange-speed mechanism.

1929. .Serial No. 379,410.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawings forming a part of this application, and 1n which:

Fig. lis a sectional elevation of a gear set;

Fig. 2 is an end elevation of the gear set showing the relative arrangement of the gear set and the driving motor;

lig. 3 is a side elevation of the gear set; an

Fig. 4 is a section on the line 4--4 of Fig. 3, showing the lever for operating the changespeed mechanism.

In accordance with a preferred embodiment of the present invention, reduction gearing is provided for receiving power from a drive shaft and for transmitting power at a reduced speed to a countershaft which is disposed preferably at substantially right angles to the drive shaft. Change-speed gearing is arranged for transmitting power from the countershaft to a driven shaft disposed substantially parallel to th'e countershaft, sufficient space being provided by this arrangement to permit the drive shaft to be arranged transversely between the countershaft and the driven shaft and thus providing a compact arrangement for the gearing and the respective shafts. The angular arrangement of the drive shaft with respect to the other shafts also provides for disposing the driving motor at one side of the gear set where it will be out of the way and yet accessible. 4The gearing is enclosed in a casing having removable end plates in which suitable bearings are provided for the counter and the driven shaft. Bearings for the drive shaft are provided in the side walls of the casing and, in each instance, removable cover plates are provided for the bearings so that access thereto may be readily had. Furthermore, due to the arrangement whereby the motor is disposed at the side of the casing it is possible by merely removing one of the end plates to gain access to the entire interior of the casing.

In the drawings the gear set is indicated generally at 10 and comprises a casing consisting of a shell portion 11 which is provided With removable end plates 12 and 13 respectively. The countershaft 14 and the driven shaftv 15 extend in substantially parallel relation Within the casing and are spaced vertically to receive the change-speed gearing 16a. This arrangement permits the reduction gearing 16 to be disposed between the countershaft and the driven shaft and provides a compact, nested arrangement for the reduction and change-speed gearing. V'The change-speed gearing comprises a seriesfof preferably non-metallic driving 'gears`1'8, i9

and 20 held fast on the countershaft by means.

driving` gear 2O and the end plate 13. lnterposed between the gears 23 and 25 and the `gear 24'are hardened steel spacers 26. Each of the driven gears 23,` 24 andf25 is provided with a keyway 27 Which is adapted to register with the keyway 28 Whichextends: ylongitudinally of the driven shaft 15 beyond the driven gears so as to provide for movement of the slidable key 29. Each of the spacing rings 26 is arranged to fit closely about kthe driven shaft -15'so that as the key 29 is moved longitudinally through thekeyway 28 it will engage one of the rings 26 and will thereby be `forced Within the shaft 15- 'during the translation of the key from a position of operative engagement with one drivengear toY a position of operative engagement with another driven .gear, thereby4 precluding the possibility of having the .key 29 engage .more than one gear at a time. The key 29 is connected to the slidable collar-31'by means of the piny 32 Which is carriedV by the Acollar and has its depending end reduced to fit/a suitable'recess `in the end of the keysoas to Cause the latter to travel longitudinallyof the shaft with the movable collar 31; The leaf spring 33 is connected to the under sid-eef thekey and adapted to urge the key into operative engagement with one of the driven gears.

' The countershaft V14 and the driven sha-ft 15 .are mounted in suitable bearings 34, which may be roller bearings as shown, and these bearings are mounted in recesses 35 Vin the end plates V12 and 13 respectively ofthe casing. The cover plates-36 for the .bearings 34 4-aredis'posed Yin suitable recesses Ain the re'- spective end plates and are held therein by means of the screvvs 36. By virtue of'this arrangement of the cover plates 36an'd bearings 34, it is possible readily to vgain access to theV bearings for purposes ofadjustment 'or repair. YFor the purpose o'f delivering powv #er 'from the. near sel-,fte a machine V.for oner- --to theidriven shaft. tionalvrange of effective speedsmay'f be obating the latter, the driven shaft 1 5 is arranged to extend through the end plate 13 and the stuffing box 37 provided therefor.

Power delivered by a drving motor is transmitted to the countershaft byk means of the driving shaft 4() Which is disposed transversely of the casing betvveenxthe countershaft 14 and the driven shaft 15 and carries the driving Worm 41 which is in operative engagement with 'the Worm Wheel 17, the latter being -lield fast on the countershaft by the key 21. One end of the driving shaft 40 extends through the shell 11 for connection by means ofthe coupling 42 With the shaft 43 of the driving motor 44. Where the driving shaft passes lthrough the shell it 'is -journaled in a bearing 34 and galso provided With a stuing box 37 (not shown) the bearing and the stuffing boX being `arranged in the same manner as the bearing 3.4 and the stuthng box 37 provided for the driven shaft- 15. The other-end of the driving Yshaftis also journaled in a bearing 34 f(notishovvn) mounted in the Vopposite side V-of the shell 11 and provided vvithfthe cover .plate 38 ig. 3)., the shaft being lthus .supported on each side of the driving Worin by :means of bear ingswvhi'ch are easily accessible for adjust- -inent'or repair. Y

For the purpose ofi actuating `the slidable key 29 from the exterior of the casingand thereby obtainingkthe desired speed .ratio through the change-speed gearing, vthe olfset bellr crank 45 (1Fig..4) `is journaledin .the boss '46 of the shell 11Land vhas one arm 47 disposed outside of thelshell and provided with the actuating handle 48,Whi'le the Vother arm 149 of this bell. crank is disposed inside the 'shell and carries v.the shoe 49 Which `rides. in the groove -of the collar '31. It Will be understood therefore that by operating the handle 48 the collar31 maybe positioned for effecting engagement of the key 29 .With any one of the driven gears 23, 24 or 25. :In this Wayit is possible vto 'utilize :any of the ratios provided by the changespeed gearing for transmitting power from the countershaft In order that ain addr tainedLand also for `the purpose of permitting Yalcliange of speed to be effected Without'af- .footing the` driven machine, the cone driving pulleyv 52y is loosely mounted, eXteriorly of 'the casing, on the driven shaft 15 and is held lin proper position thereon by means ofthe 1; collarj53 which is fastened to lthe shaft Vby the pin 54.'V The pulley 52 is operatively -conne'cted't'o the shaft 16 by means of the clu'tch56 vvhich is controlled by the rocker armf57 acting through vthe slidable'col'lar 58 `2 and the arm '59 of the clutch. The rocker .arm 57 is :held fast on the 'pin '61 bythe set screw k62 and -this pin 61 journaled in the bracket 63 Which-is carried preferablyby the cover pl-after36.k The rocker 'arm'57 is noraio mally urged in a position to hold the clutch out of engagement With the pulley 52 by the spring 64 which is disposed kin the seats 65 and 66 in the end plate 13 and in the end of the rocker arm 57 respectively. The pin 61 also carries an arm 67 Which projects laterally from the pin so that it may serve as an actuating rod for effecting engagement of the clutch. If desired, this arm 67 may be connected With a suitable treadle for operation by the foot of tlieoperator, thus making it possible for the operator to control the clutch and at the same time have both of his hands free for operating the machine.

While this gear is particularly Well adapted for installation beneath the bench 70 (Figs. 2 and 8) it Will be obvious that it may also be conveniently installed in other locations, ason the -floor or on the bed plate of a machine. The arrangement of the driving motor at one side of the set reduces the maXimum overall dimensions ofthe set and at the same time provides for ready access to the entire interior of the casing by merely removing one ofthe end plates, While each bearing becomes 'accessible for adjustment upon removal of its cover plate. The driving pulley 52 is also disposed adjacent the operating handle 48 for the change-speed gearing so that the driving belt may be shifted Without inconvenience.

hileonly one form of this invention has been shown and described, it Will be understood that the invention is susceptible to various changes and modifications Which Will occur to those skilled in the art to which this invention appertains, and that this invention is not limited except as indicated by the appended claims.

I claim:

l. In a device of the class described, the combination of a casing comprising a shell and removable end plates thereforfliearings mounted in the end plates, cover plates for the bearings, substantially parallel shafts mounted in the bearings, change-speed gearing mounted on the substantially parallel shafts, other bearings in the sides of the shell, a drive shaft mounted in said other bearings and disposed transversely between the substantially parallel shafts.

2. In a device of the class described, the combination of a casing comprising a shell and removable end plates therefor, bearings mounted in the end plates, cover plates for the bearings, substantially parallel shafts mounted in the bearings, change-speed gearing mounted on the substantially parallel shafts, other bearings in the sides of the shell, adrive shaft mounted in said other bearings and disposed transversely between the substantially parallel shafts, reduction gearing between the drive shaft and one of the substantially parallel shafts, and an actuating member slidable along the other of the latter shafts past the drive shaft for effecting a change in speed of said other shaft, thereby providing an accessible and yet compact, nested arrangement of parts.

Signed by me at Boston, Massachusetts this 18th day of July, 1929.

FREDERICK T. POTTER. 

